The invention relates to a method of checking a subscriber equipment identity in a subscriber equipment identity register of a mobile telephone exchange, which comprises an interface block, by means of which the mobile telephone exchange is connected to the subscriber equipment identity register arranged in connection with the mobile telephone exchange, which subscriber equipment identity register comprises lists containing subscriber equipment identities, which lists have list identities, in which method the mobile telephone exchange requests the subscriber for the subscriber equipment identity, the subscriber sends its equipment identity to the mobile telephone exchange, the mobile telephone exchange sends said subscriber equipment identity to the subscriber equipment identity register, the subscriber equipment identity register searches for the subscriber equipment identity corresponding to said subscriber equipment identity in the lists and sends the list identity of that list in which said subscriber equipment identity is found to the mobile telephone exchange and the mobile telephone exchange performs a predetermined function corresponding to the list identity.
The invention relates further to a mobile telephone exchange, in connection with which there is a subscriber equipment identity register, which comprises lists containing subscriber equipment identities, which lists have list identities.
It is known from mobile telephone systems that a mobile telephone subscriber has an identity, by which a subscriber equipment may be identified and from which appears the manufacturer of the subscriber equipment, for instance. Mobile telephone networks comprise a function, in which the subscriber equipment identity, which is in a GSM system the International Mobile Equipment Identity IMEI of the subscriber, is checked by asking the subscriber for its equipment identity. The checking is made, for example, because of a desire of ensuring that it is permitted to use this subscriber equipment in the network or, in other words, that the subscriber equipment is not stolen or marked faulty, which means that using it does not cause any interference in the network. A detailed composition of a subscriber equipment identity according to a GSM system is presented in standard GSM 03.03, Numbering, Addressing and Identification, Version 3.5.0, January 1991, ETSI. The subscriber may be requested for the subscriber equipment identity, for instance, typically each time when the subscriber equipment has established a connection with the mobile telephone exchange. One procedure for requesting for a subscriber equipment identity is set forth in GSM standard 09.02, Mobile Application Part Specification, Version 3.8.0, January 1991, ETSI, Paragraph 5.9.1, FIG. 5.9.1. The same paragraph of the same publication also presents how the subscriber equipment identity is subsequently sent to an Equipment Identity Register EIR, the connection of which to the mobile telephone exchange over an interface F is described in Paragraph 5.1 of the same standard, especially in FIG. 5.1.1.
The Equipment Identity Register EIR or some other location in the mobile telephone network comprises lists, e.g., according to the standard GSM 02.16, International MS Equipment Identities, Version 3.0.1, 1992, ETSI, which lists contain subscriber equipment identities or series of subscriber equipment identities and have list identities. The list identities used in the standard are composed of colours, which naturally indicate numerical identities, for instance. White color or identity is the identity of a list composed of all number series containing the equipment identities allocated by operators using the same mobile telephone system, here a GSM system, to the subscriber equipments permitted to be used in the networks. These number series are presented by informing beginning and end numbers of the series only, i.e. not by listing identities of individual subscriber equipments. A list marked with black color, i.e. black list identity, contains the identities of all subscriber equipments which shall be barred from using a mobile telephone network and a mobile telephone, e.g. because the subscriber equipment in question is faulty and could cause interference in the actual mobile telephone system or because the subscriber equipment is stolen. With gray color, i.e. gray list identity, may be marked a list containing the identities of the subscriber equipments the operation of which shall be monitored in the mobile telephone network, i.e. the identities of the equipments which may be faulty and may cause, e.g., interference in or unnecessary load on the mobile telephone network. On the gray list may also be put such new equipments the operation of which shall be monitored, because there is no guarantee yet that they operate free of interference. In a prior art solution, the equipment identities and International Mobile Subscriber Identifications IMSI of such faulty subscriber equipments are supposed to be reported to an Operation and Maintenance Center OMC of the mobile network. After having received the report, the staff of the OMC judges whether the subscriber in question may continue using the mobile network or whether the mobile telephone shall be denied a right to use the mobile network, i.e. whether the equipment identity of this subscriber shall be put on the black list. The operation staff may also find out the MSISDN number of the subscriber, which is the international ISDN (Integrated Services Digital Network) number of the Mobile Station, and call the subscriber and inform orally that the equipment of the subscriber is faulty or that the equipment shall be sent to maintenance.
A procedure as described above in a situation in which a subscriber equipment is, for instance; faulty and its identity has been put on the gray list is rather cumbersome for the staff of the OMC of the mobile network operator. The fact is that if a subscriber equipment identity has been put on the gray list and it is checked for instance in the lists contained in the EIR and the EIR detects that the subscriber equipment actually is on the gray list and transmits an information of the subscriber being on the gray list and of the subscriber equipment identity being checked to the OMC, then the staff of the OMC shall search for the MSISDN number of the subscriber manually and call the mobile telephone of this subscriber. Such a procedure is cumbersome, of course, and requires a large staff. Additionally, the procedure described cannot be expanded to concern informing of regular maintenances of mobile telephones attended to by mobile telephone manufacturers or transmitting another similar conditional information to mobile telephone subscribers desired. This problem is accentuated if the operator wishes to send a message to several mobile telephones in its service area.